The present invention relates to a removable vaginal device which can be used to administer medication or a spermicide.
One of the principal requirements for applying special medication to the body is that the medication remain in the desired body area for an extended period of time. For example, in the treatment of vaginal disorders, it is desirable that the medication be applied for many hours to remote regions of the vaginal canal and cervix. These regions are not readily reached by conventional vaginal suppositories due to their size and shape. Because of the structure and nature of the human vagina, inserted suppositories or ovules often do not stay in place, or, upon melting, the medication may drain out of the vagina, substantially reducing its effectiveness. In either of these cases, the medication is not maintained in the desired location for a sufficient duration of time, nor does it necessarily find its way to affected parts of the vaginal canal which are remote from the normal position of suppositories.
Prior attempts at overcoming these problems have not been satisfactory. For example, presently available medicated tampons do not extend far enough into the vaginal canal to deliver medication throughout the vaginal canal. Other medications are uncomfortable to insert and use because of their rigid structures.
Various attempts have been made to solve this problem of adequate delivery of medication to the vaginal canal, but the prior devices have been so far inadequate.
Groves, U.S. Pat. No. 3,815,600, teaches a vaginal medication to be retained within the human vaginal canal to apply medication molded thereon to the vaginal canal and cervix including a body-undissolvable stem and anchor means. However, for this device to be effective, it must be made rigid, and the rigidity can cause discomfort to many users.
Higuchi et al, U.S. Pat. No. 3,832,252, discloses a drug-delivery device for releasing medication at a controlled rate formed from a solid inner matrix containing medication dispersed therethrough surrounded by an outer membrane through which the medication diffuses. This device provides for a very slow release of medication.
Robinson, in U.S. Pat. No. 3,916,898, discloses a method for controlling estrus and ovulation in domestic animals by introducing into the vagina, and later removing, a sponge impregnated with a progestational compound. This device, however, is designed merely to increase fertility in domestic animals.
Roseman, U.S. Pat. No. 3,920,805, teaches a device for placement within a living body comprising a ring formed of a compatible polymeric material having medication in an outer coating of polymeric material which encircles a core of non-medicated polymeric material. This rigid ring may cause discomfort to the wearer.
Zaffaroni, U.S. Pat. No. 3,921,636, teaches a drug delivery device comprising a dry-permeable matrix comprising a plurality of drug reservoirs, each of which reservoirs comprises a drug surrounded by drug release rate controlling materials. This device relies on a drug release controlling material for efficacy, which release controlling material is of different structure and composition than the matrix material.
Laughlin et al, U.S. Pat. Nos. 4,031,202, and 4,067,961, discloses controlled release dosage devices for immediate delivery of any desired medicament. These devices comprise a stable, insoluble container, at least part of the wall of the container comprising a microporous membrane. The solid container may be uncomfortable to the user while it is in position in the vagina.
Roseman, U.S. Pat. No. 4,043,339, discloses devices for placement in the female human vaginal cavity for administering an abortifacient to the epithelial tissues of the vaginal cavity to produce abortion or to induce labor. A flexible, resilient, non-toxic polysiloxane elastomer is impregnated with an appropriate prostagladin.
Schopflin, U.S. Pat. No. 4,012,497, discloses a sustained release pharmaceutical composition containing one or more nonionic lypophilic drugs in a cured low temperature vulcanizable silicone elastomer excipient. The elastomer is cured in the presence of the drug.
Turning now to current contraceptive techniques, recently increasing attention has been given to the adverse reactions caused by oral contraceptives and intrauterine devices (IUD's), the two methods that are used by about 80% of the contracepting women in this country. Both the scientific and the lay presses have reported the occurrence of serious adverse side effects associated with their use, including myocardial infarction, thromboembolic disease, liver adenomas, pelvic inflammatory disease, ectopic pregnancy, and impaired fertility after discontinuing use of these methods.
Concurrent with the increased awareness of serious complications associated with the use of oral contraceptives and IUD's, there has been an increase in the number of users of barrier contraceptive methods. Research efforts have focused on the development of improved barrier contraceptive methods with the intent of providing effective, safe, convenient, and acceptable products. Barrier contraceptive methods presently in use include condoms, diaphragms, cervical caps, and spermicidal creams, foams, foaming tablets, and melting suppositories. Both the cervical cap and the diaphragm must be fitted by trained medical personnel, and must be refitted/replaced on a regular basis. Condoms may interfere with the sensations of the users, and chemical barrier contraceptives such as jellies, foams, tablets, and suppositories are often messy to use, and frequently cause irritation to the user and/or her partner; all barrier methods currently in use do not allow spontaniety since sexual activity must be interrupted.
A numer of factors influence the effectiveness of barrier contraceptives, including failure of the user to use the method correctly and consistently. A further problem influencing the effectiveness of the spermicidal foaming tablets and suppositories is the time from the insertion of the product into the vagina to the time the suppository has melted or foamed. This time varies among the different chemical barrier products. There are also considerable variations in the melting or foaming times among women using the same product. Moreover, while the effectiveness of melting or foaming suppositories is necessarily dependent on the spermicide incorporated, it will also depend on the chemical content of the base material and the dispersion of the product in the vagina.